This invention relates to a ventilation bag for a manually operable ventilation device for the artificial ventilation of humans. This bag is made of an elastic, air-impermeable material and is in the form of an elongated hollow body having an essentially circular cross section perpendicular to its longitudinal axis. It has external gripping surfaces for differentiated reduction of the volume of the hollow body and an air inlet opening and an air outlet opening. The gripping surfaces are arranged essentially concentric with the longitudinal axis and one behind the other in the direction of the longitudinal axis at at least one end of the hollow body, the diameter of the hollow body decreasing toward the at least one end having the gripping surfaces.
A ventilation bag of this type is known from DE-GM 1 872 078. There, a ventilation bag is described on whose periphery are arranged grooves for accommodating the fingers of the hand. The arrangement of the fingers is fixed by these grooves, and no other finger arrangement is readily possible with this ventilation bag. The ventilation bag is optimally designed for a defined hand size and can only be operated with difficulty by different hand sizes. The grooves for the fingers in this case radiate in relation to the groove for the thumb and form the gripping surfaces of the ventilation bag. A differentiated reduction of the volume of the hollow body is possible only to a very limited extent, because such a differentiation can only be achieved by the operator exerting greater or lesser compression. Thus, the gradation of the volume is at all times carried out subjectively on the part of the operator who has no objective assessment criterion whatsoever available to him or her. However, it is just this objective assessment of the air volume administered that is necessary to rule out injury to the person being ventilated.
A further ventilation bag is known from EP 0 091 428 and German Patent G 81 30 669.5. Here the ventilation bag consists of an elastic and preferably elongated hollow body having an essentially circular cross section, the bag having at each of its longitudinal ends an opening to which an air inlet connector and an air outlet connector, respectively, can be attached. The hollow body has, in its wall, two indentations that extend in the axial direction and are arranged at an angle of approximately 100.degree. to 140.degree. relative to each other in the cross sectional direction of the hollow body. Viewed in cross section, this results in two bag portions which are situated between the indentations, one of which is larger than the other. A person operating the ventilation bag can choose whether to grip the two indentations from the smaller bag portion or from the larger bag portion. In this way the volume of the bag can be reduced to a greater or lesser extent upon compression. The volume of gas delivered via the ventilation bag to the person to be ventilated thus depends on from which side the ventilation bag is gripped. To ventilate a child, for example, the smaller reduction in volume is achieved upon compression. In this way it is possible to take into account the different requirements of people of different sizes during artificial ventilation. However, the reduction in volume achieved in this way is to some extent inexact, because only a small part of the length of the bag is gripped at any one time by the hand of the operator so that the remaining volume is also reduced to a greater or lesser extent by the inherent elasticity of the ventilation bag. In addition, the arrangement of the indentations serving as gripping surfaces is ergonomically unfavorable leading, after prolonged ventilation with the ventilation bag, to the operator showing signs of fatigue.
An object of the present invention, therefore, is to provide a ventilation bag from which different ventilation volumes can be administered with relatively greater accuracy and in which signs of fatigue in the person operating the ventilation bag can be reduced to a minimum.